kconfig: include kernel/Kconfig.preempt from init/Kconfig

Almost all architectures include it.  Add a ARCH_NO_PREEMPT symbol to
disable preempt support for alpha, hexagon, non-coldfire m68k and
user mode Linux.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/c6x/Kconfig

@@ -110,8 +110,6 @@ config KERNEL_RAM_BASE_ADDRESS
 	default 0xe0000000 if SOC_TMS320C6472
 	default 0x80000000
 
-source "kernel/Kconfig.preempt"
-
 source "kernel/Kconfig.hz"
 
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